On a manufacturing floor, transferring of a workpiece from one device to another device is performed, and for the transfer of a workpiece, a conveyor including gripping means (specifically, a robot hand of a high speed multi-jointed robot) has been widely used. For example, in Patent Document 1 (FIG. 4), a conveyor grips a bar material serving as a workpiece held by holding means of one device with its gripping means, thereby receiving the bar material from the holding means, and conveys the received bar material to a predetermined positioning hole in the other device, and inserts the bar material from its one end part into the predetermined positioning hole, thereby transferring the bar material to the other device. In accordance with this, even if the other end part side of the bar material is processed by the one device, the other device is capable of holding the one end part side of the bar material without exerting an influence on the process.
Meanwhile, in the case where such transfer of a bar material is performed, the other end part side to the utmost extent of the bar material may be gripped as much as possible by the holding means of the one device in order to bring one end part side of the bar material to protrude to the outside from the holding means as much as possible in consideration of handling of a bar material with a short entire length (an entire length in a shaft center extending direction) in some cases. In accordance with this, the gripping means of the conveyor is capable of gripping the one end part side of the bar material, and the bar material can be received from the holding means.